Abstract: Objective To assess the clinical value of the isothermal RNA amplification assay (SAT) for detection of Mycobacterium tuberculosis in sputum, body fluid and nidus samples． Methods Seven hundred and thirty-four sputum samples, 94 samples of body fluid (including 68 thoracic effusion, 21 cerebrospinal fluid and 5 joint effusion) and 76 nidus samples collected from suspected tuberculosis patients were tested by both SAT and L-J culture. The positive isolates were identified by Gene-chip method. The samples with different results between SAT and L-J culture were tested by Mycobacterium tuberculosis PCR (PCR-TB) fluorescence diagnosis kits．The detection rates of SAT and L-J culture were analyzed by Chi-square test.  Results With the result of L-J culture as the re-ference, the sensitivity, the specificity and the coincidence rate of the sputum samples were 90.20% (30/255), 92.48% (443/479) and 91.69% (673/734), those of the fluid samples were 94.74% (18/19), 81.33% (61/75) and 84.04% (79/94), and those of the nidus samples were 100.00% (14/14), 77.42% (48/62) and 81.58% (62/76). With the result of PCR-TB as the reference, the sensitivity, the specificity and the accordance rate of the sputum samples were 96.30% (260/270), 99.35% (461/464) and 98.23% (721/734), those of the fluid samples were 96.97% (32/33), 100.00% (61/61) and 98.94% (93/94), and those of the nidus samples were 100.00% (27/27), 97.96% (48/49) and 98.68% (75/76).The detection rates the three different kinds of specimens by L-J culture and SAT were 34.74% (255/734) vs 36.24% (266/734), 20.21% (19/94) vs 34.04% (32/94), 18.42% (14/76) vs 36.84%(28/76). There was no difference in sputum samples between SAT and L-J culture (χ²=0.36, P＞0.05). However, there were significant differences in body fluids and nidus samples between SAT and L-J culture (χ²=4.55 and 6.44, all P<0.05).  Conclusion  SAT is a rapid, sensitive and specific method for detection of Mycobacterium tuberculosis in kinds of clinical samples.

Key words: Tuberculosis/diagnosis, Nucleic acid amplification techniques, Sensitivity and specificity